1. Field of the Invention
The present invention generally relates to testing of railroad telemetry radios used in intra-train communications and, more particularly, to an automated on-locomotive testing of Locomotive Control Unit (LCU) radios and End of Train (EOT) radios. The LCU and the EOT are complementary devices which communicate with each other as part of a complete information and control system required by the Federal Railroad Administration (FRA) to be used on freight trains with few exceptions.
2. Background Description
End of Train (EOT) signaling and monitoring equipment, now widely used in place of cabooses, and a Locomotive Control Unit (LCU) installed in the locomotive are used as part of an intra-train digital telemetry communications system. The EOT is typically mounted on the last car of the train and monitors brake pipe air pressure, train movement, battery condition, etc., and transmits this information as digital data over the radio frequency (RF) telemetry link to the LCU. The information monitored by the EOT and transmitted to the LCU is displayed to the crew in the locomotive. The EOT also receives RF transmissions from the LCU to control an air valve in the train's brake pipe to initiate emergency, and in some cases, service braking.
Since the proper operation of EOTs and LCUs in intra-train communications is critical, the systems are tested before each use by the railroads. Thus, after a train has been "made-up" in the rail yard and the LCU and EOT installed, a functional test is performed to verify the overall operation of both devices. This is done as part of the normal linking and arming sequence and verifies the functional operability of the system, i.e., LCU and EOT as a linked pair.
Note that this test does not check the performance limits of the LCU and EOT radios. To check radio performance, the LCU and EOT must normally be brought to a radio shop where the proper equipment is available, and requires opening the LCU and EOT enclosures to gain access to the radios. However, as described and explained herein, the subject invention permits full radio performance testing to be performed at a convenient regular interval, in situ, such as when locomotives are "shopped".